Today's Message Index:
----------------------
1. 04:38 AM - Linking 2 coax cables (Carlos Trigo)
2. 05:39 AM - Amp meter jumps when transmitting (rv7a.builder)
3. 06:42 AM - Re: Amp meter jumps when transmitting (Robert L. Nuckolls, III)
4. 06:43 AM - Re: Linking 2 coax cables (Robert L. Nuckolls, III)
5. 07:10 AM - Re: Amp meter jumps when transmitting (rv7a.builder)
6. 07:51 AM - Re: Amp meter jumps when transmitting (Dj Merrill)
7. 07:57 AM - Re: OT: power supply noise (rayj)
8. 08:22 AM - Re: Amp meter jumps when transmitting (rv7a.builder)
9. 10:07 AM - Re: Amp meter jumps when transmitting (Kevin Belue)
10. 10:55 AM - Re: Amp meter jumps when transmitting (Robert L. Nuckolls, III)
11. 11:01 AM - Re: OT: power supply noise (Robert L. Nuckolls, III)
12. 11:28 AM - Re: OT: power supply noise (rayj)
13. 03:53 PM - Re: Amp meter jumps when transmitting (Dj Merrill)
14. 04:04 PM - Re: Linking 2 coax cables (Eric M. Jones)
15. 05:24 PM - Re: Amp meter jumps when transmitting (Henador Titzoff)
16. 05:45 PM - Re: Amp meter jumps when transmitting (Robert L. Nuckolls, III)
17. 06:49 PM - Re: Amp meter jumps when transmitting (Henador Titzoff)
18. 07:51 PM - Re: Amp meter jumps when transmitting (Robert L. Nuckolls, III)
Message 1
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Subject: | Linking 2 coax cables |
Guys
I had to cut and throw away some 2 feet of a Comm antenna cable which I
found that had a burnt spot.
I don't want to replace all the coax cable, which would be a PIA to do.
I also know that I can use a male and a female BNC connectors to make a 2
feet extension, but
Is there an elegant and efficient way to connect 2 coax cables to each
other, without using a male and a female connectors?
Regards
Carlos
---
Este email est livre de vrus e malware porque a proteo avast! Antivirus est ativa.
http://www.avast.com
Message 2
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Subject: | Amp meter jumps when transmitting |
Hello Group,=0A---- I have a Vans amp meter installed in my RV-7A.
When I activate the PTT on the Garmin GNC300XL-the amp meter jumps to ful
l scale. I disconnect the antenna coax from back of the radio and hit the P
TT and the amp meter needle stays still. I turn off the radio and bring my
handheld into the cockpit and hit the transmit button from 2 feet away-an
d a very slight movement in the amp meter is detected.-Bringing the handh
eld closer to the amp meter will make the needle jump more when the PTT is
activated.-I think I have-determined this to be a RF-inference proble
m.-My questions are 1) Will the amp meter eventually be damaged by these
extreme movements? 2) Is there a fix? 3) Am I alone here or have others exp
erience this phenomena?=0A-=0AThanks. John. RV-7A Just about ready to fly
Message 3
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Subject: | Re: Amp meter jumps when transmitting |
At 07:35 AM 4/27/2014, you wrote:
Hello Group,
I have a Vans amp meter installed in my RV-7A. When I activate
the PTT on the Garmin GNC300XL the amp meter jumps to full scale. I
disconnect the antenna coax from back of the radio and hit the PTT
and the amp meter needle stays still. I turn off the radio and bring
my handheld into the cockpit and hit the transmit button from 2 feet
away and a very slight movement in the amp meter is detected.
Bringing the handheld closer to the amp meter will make the needle
jump more when the PTT is activated. I think I have determined this
to be a RF inference problem.
I bought a Van's ammeter some years ago to
explore it's vulnerabilities to strong RF.
See pictures here:
http://tinyurl.com/mpx8hze
I discovered that no only was the instrument
devoid of any firewall for RF interference,
it was even directionally sensitive!!! See
pictures
http://tinyurl.com/m4xlj2u
http://tinyurl.com/kvo4vwk
Just waving the hand-held from side to side
would produce behaviors in the pointer error
that mimicked the motion of the antenna.
My questions are 1) Will the amp meter eventually be damaged by these
extreme movements?
No
2) Is there a fix?
Probably, but labor intensive and clumsy on
a finished instrument. It would have been FAR
better that the manufacturer demonstrated
a knowledge of DO-160 in the first place.
3) Am I alone here or have others experience this phenomena?
No doubt there are many others. Since it's
a transient event that affects the display
only while talking, it's a cosmetic behavior.
You might consider just 'living' with it.
With one caveat . . . make sure that your coax
connectors are good at both ends of the feedline . . .
it wouldn't hurt to do an SWR check. The
phenomenon you're observing MIGHT be the
result of a very RF-Hot cockpit due to loss
of shield ground on either end of the coax.
But it your antenna system is golden, then
there are no risks for just ignoring it.
I wrote to Van's about this condition . . . never
heard back from them. It no doubt affects
their entire line of instruments with
electronic signal conditioning.
Bob . . .
Message 4
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Subject: | Re: Linking 2 coax cables |
At 06:37 AM 4/27/2014, you wrote:
><trigo@mail.telepac.pt>
>
>Guys
>
>I had to cut and throw away some 2 feet of a Comm antenna cable which I
>found that had a burnt spot.
>I don't want to replace all the coax cable, which would be a PIA to do.
>I also know that I can use a male and a female BNC connectors to make a 2
>feet extension, but
>Is there an elegant and efficient way to connect 2 coax cables to each
>other, without using a male and a female connectors?
Yeah, sort of but it's pretty process sensitive.
I'd vote for the connectors.
Bob . . .
Message 5
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Subject: | Re: Amp meter jumps when transmitting |
Thanks Bob for that great analysis. John.=0AOn Sunday, April 27, 2014 6:57
AM, "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com> wrote:=0A
olls.bob@aeroelectric.com>=0A=0AAt 07:35 AM 4/27/2014, you wrote:=0AHello G
roup,=0A- - - I have a Vans amp meter installed in my RV-7A. When I a
ctivate =0Athe PTT on the Garmin GNC300XL the amp meter jumps to full scale
. I =0Adisconnect the antenna coax from back of the radio and hit the PTT
=0Aand the amp meter needle stays still. I turn off the radio and bring =0A
my handheld into the cockpit and hit the transmit button from 2 feet =0Aawa
y and a very slight movement in the amp meter is detected. =0ABringing the
handheld closer to the amp meter will make the needle =0Ajump more when the
PTT is activated. I think I have determined this =0Ato be a RF inference p
roblem.=0A=0A- - I bought a Van's ammeter some years ago to=0A- - e
xplore it's vulnerabilities to strong RF.=0A=0A- - See pictures here:
=0A=0Ahttp://tinyurl.com/mpx8hze=0A=0A- - I discovered that no only was
the instrument=0A- - devoid of any firewall for RF interference,=0A-
- it was even directionally sensitive!!! See=0A- - pictures=0A=0Ahtt
p://tinyurl.com/m4xlj2u=0A=0Ahttp://tinyurl.com/kvo4vwk=0A=0A- - Just w
aving the hand-held from side to side=0A- - would produce behaviors in
the pointer error=0A- - that mimicked the motion of the antenna.=0A=0A
=0AMy questions are 1) Will the amp meter eventually be damaged by these
=0Aextreme movements?=0A=0A- - No=0A=0A- 2) Is there a fix?=0A=0A-
- Probably, but labor intensive and clumsy on=0A- - a finished instru
ment. It would have been FAR=0A- - better that the manufacturer demonst
rated=0A- - a knowledge of DO-160 in the first place.=0A=0A- 3) Am I
alone here or have others experience this phenomena?=0A=0A=0A- - No dou
bt there are many others. Since it's=0A- - a transient event that affec
ts the display=0A- - only while talking, it's a cosmetic behavior.=0A
- - You might consider just 'living' with it.=0A=0A- - With one cav
eat . . . make sure that your coax=0A- - connectors are good at both en
ds of the feedline . . .=0A- - it wouldn't hurt to do an SWR check.-
The=0A- - phenomenon you're observing MIGHT be the=0A- - result of
a very RF-Hot cockpit due to loss=0A- - of shield ground on either end
of the coax.=0A=0A- - But it your antenna system is golden, then=0A-
- there are no risks for just ignoring it.=0A=0A- - I wrote to Van's
about this condition . . . never=0A- - heard back from them. It no doub
t affects=0A- - their entire line of instruments with=0A- - electro
===============
Message 6
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Subject: | Re: Amp meter jumps when transmitting |
On 4/27/2014 8:35 AM, rv7a.builder wrote:
> I disconnect the antenna coax from back of the radio and hit the PTT
> and the amp meter needle stays still.
Just as an aside, it is generally a bad idea to activate a transmitter
with no antenna attached. There is a good chance of damaging the
transmitter by doing this.
fyi
-Dj
--
Dj Merrill - N1JOV - VP EAA Chapter 87
Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/
Glastar Flyer N866RH - http://deej.net/glastar/
Message 7
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Subject: | Re: OT: power supply noise |
The parts were part of the CNC kit I bought years ago. It is the power
supply for the stepper motors. The output is in the neighborhood of 5
amps at 38Vdc The kit specified an UNregulated power supply because of
problems associated with back emf from the stepper motors as they
decelerate, as I understand it.
The motor drivers derive the required 5Vdc internally from the power
supply hookup.
My main concern was about radiated noise being picked up because they
are both inside an old metal computer case.
Thanks for the reply.
Raymond Julian
Kettle River, MN
The things we admire in men, kindness and generosity, openness, honesty,
understanding and feeling are the concomitants of failure in our system.
And those traits we detest, sharpness, greed, acquisitiveness, meanness,
egotism and self-interest are the traits of success. And while men
admire the quality of the first they love the produce of the second.
-John Steinbeck, novelist, Nobel laureate (1902-1968)
On 04/26/2014 10:56 PM, Robert L. Nuckolls, III wrote:
> <nuckolls.bob@aeroelectric.com>
>
> At 03:10 PM 4/26/2014, you wrote:
>>
>> Greetings,
>>
>> I'm considering putting an unregulated power supply (transformers,
>> diodes, and a condenser) in an old computer box along with the
>> electronics to run several stepper motors for a CNC system.
>>
>> I'm wondering if noise radiated from the power supply will cause
>> problems for the stepper motor drivers.
>
> Probably not. Do you have these parts already in hand?
> Regulated, clean power supplies up to 350W are pretty
> cheap on eBay. I seldom build a supply any more, the labor
> alone is more than the cost of an off-the-shelf, plug-n-play
> device.
>
>
> Bob . . .
>
>
Message 8
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Subject: | Re: Amp meter jumps when transmitting |
Thanks for telling me that. I won't try that again. What actually happens t
hat could damage the transmitter? Thanks. John=0AOn Sunday, April 27, 2014
8:10 AM, Dj Merrill <deej@deej.net> wrote:=0A =0A--> AeroElectric-List mes
sage posted by: Dj Merrill <deej@deej.net>=0A=0AOn 4/27/2014 8:35 AM, rv7a.
builder wrote:=0A> I disconnect the antenna coax from back of the radio and
hit the PTT =0A> and the amp meter needle stays still.=0A=0AJust as an asi
de, it is generally a bad idea to activate a transmitter =0Awith no antenna
attached.- There is a good chance of damaging the =0Atransmitter by doin
g this.=0A=0Afyi=0A=0A-Dj=0A=0A-- =0ADj Merrill - N1JOV - VP EAA Chapter 87
=0ASportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/=0AGlasta
Message 9
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Subject: | Re: Amp meter jumps when transmitting |
I saw this problem years ago also. Their electronic manifold pressure gauge has
same issue. I replaced the MP with a non-electric version. The rest of my instruments
are from an EFIS. No problems with this configuration.
K. Belue
RV-10
Sent from my iPhone
On Apr 27, 2014, at 8:41 AM, "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
wrote:
>
> At 07:35 AM 4/27/2014, you wrote:
> Hello Group,
> I have a Vans amp meter installed in my RV-7A. When I activate the PTT on
the Garmin GNC300XL the amp meter jumps to full scale. I disconnect the antenna
coax from back of the radio and hit the PTT and the amp meter needle stays
still. I turn off the radio and bring my handheld into the cockpit and hit the
transmit button from 2 feet away and a very slight movement in the amp meter
is detected. Bringing the handheld closer to the amp meter will make the needle
jump more when the PTT is activated. I think I have determined this to be a
RF inference problem.
>
> I bought a Van's ammeter some years ago to
> explore it's vulnerabilities to strong RF.
>
> See pictures here:
>
> http://tinyurl.com/mpx8hze
>
> I discovered that no only was the instrument
> devoid of any firewall for RF interference,
> it was even directionally sensitive!!! See
> pictures
>
> http://tinyurl.com/m4xlj2u
>
> http://tinyurl.com/kvo4vwk
>
> Just waving the hand-held from side to side
> would produce behaviors in the pointer error
> that mimicked the motion of the antenna.
>
>
> My questions are 1) Will the amp meter eventually be damaged by these extreme
movements?
>
> No
>
> 2) Is there a fix?
>
> Probably, but labor intensive and clumsy on
> a finished instrument. It would have been FAR
> better that the manufacturer demonstrated
> a knowledge of DO-160 in the first place.
>
> 3) Am I alone here or have others experience this phenomena?
>
>
> No doubt there are many others. Since it's
> a transient event that affects the display
> only while talking, it's a cosmetic behavior.
> You might consider just 'living' with it.
>
> With one caveat . . . make sure that your coax
> connectors are good at both ends of the feedline . . .
> it wouldn't hurt to do an SWR check. The
> phenomenon you're observing MIGHT be the
> result of a very RF-Hot cockpit due to loss
> of shield ground on either end of the coax.
>
> But it your antenna system is golden, then
> there are no risks for just ignoring it.
>
> I wrote to Van's about this condition . . . never
> heard back from them. It no doubt affects
> their entire line of instruments with
> electronic signal conditioning.
>
>
>
>
>
> Bob . . .
>
>
>
>
Message 10
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Subject: | Re: Amp meter jumps when transmitting |
At 09:50 AM 4/27/2014, you wrote:
>
>On 4/27/2014 8:35 AM, rv7a.builder wrote:
>>I disconnect the antenna coax from back of the radio and hit the
>>PTT and the amp meter needle stays still.
>
>Just as an aside, it is generally a bad idea to activate a
>transmitter with no antenna attached. There is a good chance of
>damaging the transmitter by doing this.
Back in the days of germanium output transistors
(yes Martha, there WERE germanium devices capable
of several watts at VHF) it was considered poor
form if not instant death to one's output transistors
to key a transmitter into an open circuit.
Modern output devices are much more rugged. Further,
transmitters at-risk for high SWR damage are fitted
with automatic shut-down circuits for protection.
Bob . . .
Message 11
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Subject: | Re: OT: power supply noise |
At 09:56 AM 4/27/2014, you wrote:
>
>The parts were part of the CNC kit I bought years ago. It is the
>power supply for the stepper motors. The output is in the
>neighborhood of 5 amps at 38Vdc The kit specified an UNregulated
>power supply because of problems associated with back emf from the
>stepper motors as they decelerate, as I understand it.
Steppers don't generate back emf based on
motion of the moving parts. For the fastest
possible response time, steppers like to be
driven from high resistance if not purely constant
current power sources. It's all about that
t=L/R thingy.
The first stepper systems I crafted used banks
of power resistors to raise power source impedance.
Modern designs will use constant current output
stages in the drivers if they're seeking high
accuracy positioning along with fast response.
>The motor drivers derive the required 5Vdc internally from the power
>supply hookup.
>
>My main concern was about radiated noise being picked up because
>they are both inside an old metal computer case.
Your application would run quite well from unregulated,
full wave rectified AC as long as the 'relaxed' voltage
is not so high as to place output transistors at risk
in their OFF state.
Bob . . .
Message 12
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Subject: | Re: OT: power supply noise |
Thanks. Now out to the shop!
do not archive
Raymond Julian
Kettle River, MN
The things we admire in men, kindness and generosity, openness, honesty,
understanding and feeling are the concomitants of failure in our system.
And those traits we detest, sharpness, greed, acquisitiveness, meanness,
egotism and self-interest are the traits of success. And while men
admire the quality of the first they love the produce of the second.
-John Steinbeck, novelist, Nobel laureate (1902-1968)
On 04/27/2014 01:00 PM, Robert L. Nuckolls, III wrote:
> <nuckolls.bob@aeroelectric.com>
>
> At 09:56 AM 4/27/2014, you wrote:
>>
>> The parts were part of the CNC kit I bought years ago. It is the
>> power supply for the stepper motors. The output is in the
>> neighborhood of 5 amps at 38Vdc The kit specified an UNregulated power
>> supply because of problems associated with back emf from the stepper
>> motors as they decelerate, as I understand it.
>
> Steppers don't generate back emf based on
> motion of the moving parts. For the fastest
> possible response time, steppers like to be
> driven from high resistance if not purely constant
> current power sources. It's all about that
> t=L/R thingy.
>
> The first stepper systems I crafted used banks
> of power resistors to raise power source impedance.
> Modern designs will use constant current output
> stages in the drivers if they're seeking high
> accuracy positioning along with fast response.
>
>> The motor drivers derive the required 5Vdc internally from the power
>> supply hookup.
>>
>> My main concern was about radiated noise being picked up because they
>> are both inside an old metal computer case.
>
> Your application would run quite well from unregulated,
> full wave rectified AC as long as the 'relaxed' voltage
> is not so high as to place output transistors at risk
> in their OFF state.
>
>
> Bob . . .
>
>
Message 13
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Subject: | Re: Amp meter jumps when transmitting |
On 4/27/2014 11:21 AM, rv7a.builder wrote:
> Thanks for telling me that. I won't try that again. What actually
> happens that could damage the transmitter? Thanks. John
Hi John,
I am sure someone else on here can explain the technical details
better than I, but the simple version is that if the transmitter does
not have circuitry built in to protect against it, it can blow some of
the parts in the final amplifier stage of the transmitter. Hopefully
someone else can chime in with more details of exactly how and why.
There is probably a good chance that a modern solid state radio has
this protection built in, but unless one knows for sure, there is no
reason to take the expensive chance that it doesn't. I'd be more
concerned with the older radios, but in general it is just good practice
to make sure that you have an antenna or a dummy load attached to the
antenna port before keying up the transmitter. My personal choice is to
make sure there is an antenna attached before even powering a radio on,
regardless of whether I am going to key the transmitter part.
-Dj
--
Dj Merrill - N1JOV - VP EAA Chapter 87
Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/sportsman/
Glastar Flyer N866RH - http://deej.net/glastar/
Message 14
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Subject: | Re: Linking 2 coax cables |
Install a new cable or connectors. No other reasonable solution exists. Read my
article attached.
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=422475#422475
Attachments:
http://forums.matronics.com//files/dabbling_with_electricity_179.pdf
Message 15
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Subject: | Re: Amp meter jumps when transmitting |
Dj, John,=0A=0AHere's what happens when a transmitter hurls RF energy down
a transmission line.- First, the transmission line has a characteristic i
mpedance.- Impedance is almost like a resistance except it's comprised of
a mixture of capacitor reactance, inductive reactance and resistance.- R
eactances have currents and voltages that are 90 degrees out of phase.- T
his means they don't "burn" up any of the energy, whereas resistance has vo
ltage and current in phase and does burn up energy.- Check out the attach
ed picture from Wiki, which shows how the capacitance, inductance and resis
tances are modeled as lumped components. Ideally, the series and parallel r
esistances are zero.- In practice they're not but designers try to minimi
ze them to decrease attenuation.=0A=0A=0AWhen this energy traveling down th
e transmission line reaches the end, what happens?- If there's a resistor
there that is equal to the transmission line's characteristic impedance, t
hen ideally all of the energy is dissipated in that resistor as heat, since
the voltage and current waves are in phase.- If an antenna that is match
ed to the line is there, the power is magically transferred to the atmosphe
re, because the antenna's job is to match the impedance of the cable to fre
e space impedance, which is 376 Ohms.- It isn't really magic, at least ma
thematically, but one has to understand Maxwell's and Gaussian's laws to kn
ow how this happens and why free space impedance is 376 Ohms.=0A=0A=0ASo le
t's say the end of the transmission line is open or doesn't match the imped
ance.- In the open case, the energy has nowhere to go except to be transm
itted right back to where it came from.- Let's say the transmitter's tran
sistors are generating voltage waves that are 10V peak to peak.- This mea
ns that the designer has to choose components that can handle this voltage
plus some, say another 10V, in order to provide longevity and reliability.
- When the reflected energy arrives at the transmitter output, the two wa
ves (one going and one coming) can add up to a worst case number of 20V pea
k to peak if the phasing is correct. This comes very close to exceeding the
design limitation of the transmitter transistors.- If the designer specs
the transistors to less than 20V, then the two added waves' peak voltage c
ould very well destroy the transistors and/or other components.- The desi
gner could add transorbers or some other devices designed to limit the
voltage build up at the transmitter to keep it from malfunctioning, but it
's up to the designer and his design specs.=0A=0AAlso, the transmitter has
an impedance of its own, and for maximum power transfer it should equal the
line's impedance.- When the reflected wave comes back, if there is a sli
ght mismatch between the transmitter and line impedances, there will be som
e power dissipation at the transmitter but some of the power (wave) will re
flect back to the end of the line.- This means there are several waves on
the line, but each reflection decreases in amplitude because of losses alo
ng the line and at the ends.- All of these waves have to be added or subt
racted to find the real voltages at the ends.=0A=0ASo the bottom line is ca
n the transmitter handle the reflected waves such that when they add up, th
e end voltage doesn't damage the transmitter components, which of course ha
ve maximum voltage and power limits.- I add power in there because power
causes heat and components can only handle so much maximum temperature.=0A
=0AHope this helps.=0A-=0AHenador Titzoff=0A=0A=0A>______________________
__________=0A> From: Dj Merrill <deej@deej.net>=0A>To: aeroelectric-list@ma
tronics.com =0A>Sent: Sunday, April 27, 2014 6:52 PM=0A>Subject: Re: AeroEl
ectric-List: Amp meter jumps when transmitting=0A> =0A>=0A>--> AeroElectric
-List message posted by: Dj Merrill <deej@deej.net>=0A>=0A>On 4/27/2014 11:
21 AM, rv7a.builder wrote:=0A>> Thanks for telling me that. I won't try tha
t again. What actually =0A>> happens that could damage the transmitter? Tha
nks. John=0A>=0A>Hi John,=0A>- - I am sure someone else on here can ex
plain the technical details =0A>better than I, but the simple version is th
at if the transmitter does =0A>not have circuitry built in to protect again
st it, it can blow some of =0A>the parts in the final amplifier stage of th
e transmitter. Hopefully =0A>someone else can chime in with more details of
exactly how and why.=0A>=0A>- - There is probably a good chance that
a modern solid state radio has =0A>this protection built in, but unless one
knows for sure, there is no =0A>reason to take the expensive chance that i
t doesn't.- I'd be more =0A>concerned with the older radios, but in gener
al it is just good practice =0A>to make sure=0A that you have an antenna or
a dummy load attached to the =0A>antenna port before keying up the transmi
tter.- My personal choice is to =0A>make sure there is an antenna attache
d before even powering a radio on, =0A>regardless of whether I am going to
key the transmitter part.=0A>=0A>-Dj=0A>=0A>-- =0A>Dj Merrill - N1JOV - VP
EAA Chapter 87=0A>Sportsman 2+2 Builder #7118 N421DJ - http://deej.net/spor
========================0A>
=0A>=0A>=0A>=0A>=0A>
Message 16
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Subject: | Re: Amp meter jumps when transmitting |
>So the bottom line is can the transmitter handle the reflected waves
>such that when they add up, the end voltage doesn't damage the
>transmitter components, which of course have maximum voltage and
>power limits. I add power in there because power causes heat and
>components can only handle so much maximum temperature.
I'm aware of no supplier to aviation that does not
consider the rare but possible failure of a coax
connection . . . it's common practice to build
in protection, robustness or a combination of the
two.
Bob . . .
Message 17
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Subject: | Re: Amp meter jumps when transmitting |
This is very true, Bob, but I would also like to add that the possibility o
f an open in the connectors and coax is more common than "rare."- Most of
these failures occur during build, which are accidental, corrosion or fail
ure to tighten down connectors correctly.=0A=0A=0AWhile aviation suppliers
will consider the rare but possible failure you mention below, there are se
veral scenarios where this is not true.- One scenario is the supplier rec
eiving counterfeit parts that do not meet specs.- Another scenario is a s
hady buyer ordering the wrong parts and a faulty lot is manufactured and sh
ipped.- Manufactured lots vary from lot to lot, and some lots may sneak t
hrough that do not meet specifications but work well until "something happe
ns."- In particular, this business of counterfeit parts has been plaguing
manufacturing for at least two decades now.=0A=0A-=0AHenador Titzoff=0A
=0A=0A>________________________________=0A> From: "Robert L. Nuckolls, III"
<nuckolls.bob@aeroelectric.com>=0A>To: aeroelectric-list@matronics.com =0A
>Sent: Sunday, April 27, 2014 8:44 PM=0A>Subject: Re: AeroElectric-List: Am
p meter jumps when transmitting=0A> =0A>=0A>--> AeroElectric-List message p
osted by: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>=0A>=0A>
=0A>>So the bottom line is can the transmitter handle the reflected waves
=0A>>such that when they add up, the end voltage doesn't damage the =0A>>tr
ansmitter components, which of course have maximum voltage and =0A>>power l
imits.- I add power in there because power causes heat and =0A>>component
s can only handle so much maximum temperature.=0A>=0A>- - I'm aware of
no supplier to aviation that does not=0A>- - consider the rare but poss
ible failure of a coax=0A>- - connection . . . it's common practice to
build=0A>- - in protection, robustness or a combination of the=0A>-
==================0A>=0A>=0A>=0A>=0A>=0A>
Message 18
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Subject: | Re: Amp meter jumps when transmitting |
> >Manufactured lots vary from lot to lot, and some lots may sneak
> through that do not meet specifications but work well until
> "something happens." In >particular, this business of counterfeit
> parts has been plaguing manufacturing for at least two decades now.
Forgive me my friend but we're reaching WAAaaayyyy down into
the worry bucket with this line of reasoning. Once
you open that door . . . where do the caveats end?
Cracked magneto rotors? Contaminated fuel? Bogus rivets?
The world is indeed fraught with risks. Nonetheless,
the vast majority of misadventures in every
venue have nothing to do with parts that fail
to meet published requirements. Adding such
worries to the knowledge base is potential misdirection
of valuable attention from much greater risks.
Bob . . .
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